package bishizhuanyong.网易;

import java.util.Scanner;

public class Main3 {

    public static void main(String[] args) {
        Scanner s=new Scanner(System.in);
        int n = s.nextInt();
        int k = s.nextInt();
        int t = s.nextInt();
        int one= k;
        int zero=n-one;
        if (n<one){
            System.out.println(-1);
            return;
        }
        if (t+1>k){
            System.out.println(-1);
            return;
        }
        int cur_match=zero-1;
        if (cur_match-t>zero){
            System.out.println(-1);
            return;
        }
        StringBuffer sb=new StringBuffer();
        for (int i=0;i<t+1;i++)
            sb.append(1);
        int reamin_one=one-sb.length();
        for (int i=0;i<zero;i++) {
            sb.append(0);
            if (reamin_one>0){
                sb.append(1);
                reamin_one--;
            }
        }
        if (sb.length()!=n){
            System.out.println(-1);
            return;
        }
        System.out.println(sb.toString());
    }
}
